1. Technical Field
The present invention relates to a technical field of an electrooptic device such as a liquid crystal device, a method for manufacturing the same, and a structure for electrically connecting conductive parts such as wires or electrodes of a semiconductor device.
2. Related Art
Liquid crystal devices, examples of this type of electrooptic device, often have a holding capacitor in parallel with a liquid-crystal capacitor to prevent the leakage of image signals held in a pixel section. For example, JP-A-2001-290171 (Patent Document 1) discloses a method for manufacturing the holding capacitor. By the method disclosed in Patent Document 1, the distance between the edge of the contact hole for contact with the wire above the upper electrode and the upper electrode of the holding capacitor is determined by two kinds of mask patterns, thus providing electrical insulation, the contact hole being connected to the lower electrode of the holding capacitor.
However, the electrical connection between the lower electrode of the holding capacitor and the wire above the upper electrode via the contact hole using the two kinds of masks, as in the technique of Patent Document 1, has the technical problem of difficulty in expanding the open area of the pixel. More specifically, to form a contact hole in a region where non-optical-transmitting elements that block light that is to pass through the pixel, such as wires, light-shielding films, or semiconductor devices, are formed, it is necessary to design the contact hole while ensuring a margin in consideration with the registration of the two kinds of mask so as to partly remove the insulating layer where the contact hole is to be formed. This increases the proportion of the unopen area of the pixel by an amount corresponding to the margin, posing the problem of difficulty in increasing the display quality due to the high percentage of the unopen area of the pixel.
Furthermore, this arrangement has the problem encountered on designing that the unuseful area of the semiconductor device is increased due to the contact hole which is formed to electrically connect the conductive parts on different layers, such as wires, so that it becomes difficult to minimize the device.